Benitez talks to his fellow Spaniards, including striker Torres and goalkeeper Pepe Reina, in English and expects them to do the same.
Torres said: "There are 12 Spanish speakers but we try not to talk in Spanish because if he catches us, Rafa fines us.
"He always speaks in English to the Spanish, except when there's something you don't understand. At the start it was difficult. But with every day, I'm getting to know the language and the city better."